Claw-lever-and-rack-actuated parallel jaw wrench



A. LAZZARINI March 14, 1950 CLAW-LEVER-AND-RACK-ACTUATED PARALLEL JAW WRENCH Filed June 25, 1947 a 6 1 xo Patented Mar. 14, 1950 UNITED STATES PATENT OFFICE 'I CLAW-LEVER-AND-RACK-ACTUATED PARALLEL J AW WRENCH 3 Claims.

My invention relates to improvernerts in wrenches of the type having the jaw-"always parallel to one another regardless of the aperture to which it is held.

The objects of my invention are: Firstto produce a wrench which will have a very powerful grip due to its high leverage, without permanently limiting the range of displacement of the jaws to relatively small apertures; and second-to incorporate in it certain mechanical fee tures affording utmost ease and speed in preadjusting its jaws to a slightly wider aperture than that required for the work at hand.

I attain these objects with a mechanical tool whose design is illustrated in the accompanying drawings and whose operation will be henceforth described:

Fig. 1 is a view o-f this tool as one would see by removing one side wall of that portion which constitutes the housing. In this figure the working position represented is the open one.

Fig. 2 is a similar View as the above, but showing the wrench in the closed position.

Fig. 3 is a sectional view of the upper part of the wrench, or body (for space convenience the handle portion is broken away), along line 3--3 of Fig. 2.

Similar numerals refer to the same parts as illustrated in all figures.

A main part, designated with small numeral l, constitutes a housing enclosing the other parts of the tool's body. It is formed by two flat walls held parallel by return portions 2 and 3. A tapering elongation 4, extending downward, forms one of the pair of handles of the wrench. Also, one of the jaws, 5, is integrally a part of the same housing, straddling the two flat walls of the same at the top.

An oblong perforation in both walls of the housing is indicated by dotted line at 6. These perforations preferably follow an oblique direction for a purpose which will be later explained. They are designed to accommodate a fulcrum pin 'I and also allow the same a certain extent of shifting motion, as respectivelyillustrated in Fig. 1 (down) and Fig. 2 (up). Obviously the perforations of the two walls will be perfectly aligned.

A lever 8 provides the second handle of the usual pair. Its upper portion forms a head 9 upon whose summit is cut a gear sector IO, Through an appropriate perforation co-centered with the gear sector, fulcrum pin 'I is forced in, being locked therein by `friction and symmetrically protruding its ends into the perforations 6 of the side walls, as shown in Fig. 3.

A toothed bar, or rack, H, which has a section profile similar to a T turned upside-down (see Fig. 3), is slidably fitted to suitable guiding tracks 2 !2, formed at the upper edge of the walls of the housing l and projecting inwardly.

The teeth of such rack are intermeshable with the gear sector IO.

Both the gear sector IO and rack H are as broad and strong as feasible, their teeth extending in width from wall to wall of the housing.

The other jaw of the pair, [3, is an integral part of rack l l, the latter .being its sliding base.

Located between the fiat walls of the housing I is a partition !4 which will provide a small compartment for a spring-and-ball latch !5, while a small pin !6 will retain the spring of same at the bottom and provide convenientaccess for assembling the parts.

The ball of said latch is pressed by the spring over and in between the teeth of rack ll, causing said rack to normally stop at a varied degree of displacement along its tracks as may be induced by manipulation. g

The lever head, 9, forms a curved projection, IT, in its profile, the purpose of` which is to operate as a cam.

A roller, 18, held in place by pin e, is adjacent to said cam and will operate in contact with the latter. i

A lobe 20, outgrowing from lever-head 9, has a small hole within which is hooked one end of a stretching coil spring ZI. The other end of said spring is anchored by pin 22 to a point in the channel formed by the housing's handle extension 4.

Said lobe 20 of the lever-head and said coil spring 2l, need not be considered essential to the operation of this invention, and may be dispensed with. In such case the lever-head 9 may be caused to drop as the handle 8 is allowed to Swing open by gravity or by finger manipulation.

The normal inoperative position of this wrench would be as illustrated in Fig. 1 with the two handles, 4 and 8, spread far apart, due to the pull of spring 2 However, it may be convenient for the purpose of storage, to make possible the retention of the closed position when the wrench is not in use. A slight depression of the cam profile at the point of contact with roller !8 which corresponds to the close position of the wrench will effect that. This point is indicated by a small arrow 23 in Fig. 2.

In putting this tool to use, the first step is to spread the handles apart if they don t happen already to be. This is done with a slight-jerk of the small finger's knuckle, which will immediately activate spring 2I in overcoming the small depression 23 in the cam.

The action of spring ZI, not only will cause the handles to spread apart, but as the cam 'l'l rides over roller IB, When it has reached a cer tain point the whole lever-handle 8, will commence to descend and may go down as far as u 3 r allowed by the play of fulcrum pin T'within the oblong perforatiors 6 of the housing walls. When this has occurred the teeth of gear sector u will have-becomedisengaged from those of racki ll. to shuttle one way or the other by hand-pressing In this situation, the rack l l'is readily caused" the jaws together or, reversely, by pressing the' jutting end of the rack ll into thethousing: The:

spring-and-ball latch will momentarily hold it in the desired position. Thus an aperture is set for the wrench's jaws which is most suitable for' the work to be performed, that is,an aperture slightly wider than the gripping hold will attain.

By experimentation ithas been found that the effective displacement needed for the jaws to serve* in" all' situations, correspo-nds to* slightly because'the spring-and-b'a-ll latch will hold' the M rack` and its teeth in true" position for the approach of the gear'sector. Then the cam` IT, riding its' arched contourover the roller !8, will allow pivoting of the handle-lever at the point where fulcrum-pin 1 sits-atthetop of the oblong' perforations'of the housing; `Thus the rack H impelled to slide and orce the jaws to close. This' is the positive g-ripping action. As itinvolves=a small'displacement of the jaws, and as: the ratio of leverage (lever-handle length: gear# sector 10, upon'the resisting rack' I 1-, would'tend 401* to cause the meshed teeth to slide off engage ment. To prevent that, the counter-thrust developed by'fLl'crum-pinl, which is' in the' opposite direction; is taken advantage of. e

The'wall perforations t, as shown in thedraw ings, are cut in an oblique direction. They could be Vertical without prejudice to the functionng of'the' instrument; However, the oblique cut` is preferred in order to cause'a slanted-rising 'motion': ofthe gear'sector which will obviate any:disp1ace.-- ment of the'toothedra'ck: ll before the-teeth arez completely intermeshed..

To release-theiholding grip, it willion'ly be nec' essary to ease' the hand'pressure` from the handl'es. 'Ph'e spring 21 being' under tension will? pulla. om robe za and cause' allmovin'g'parts to return' to: the" open' position;

Having "thus described" myrinvention', I claim 1. A` parallel Wrench' composed' of' a. housing: body having two' main walls; a-.forwardly pro& jectihg stationary'jaw adjacent' one: edge and as fixed handle extending* rearwardly at the oppo site-edge, a' movablezj 'aw oppo'sing :saidlstationaryx jaw and having a toothe'd rack'slidable trans- Versely' within' the housing: body; a` stationary roller; a:-conpositeelementforminga lever and headwith: a gear sector 'at: oneend and opposingtheteeth-otth'e -rack;saidheadalso :having a? profile', the' latter: being operable:: upon; the.

roller, said roller being positioned:: within; the:

housing between the fixed` handle and the;` cam profile. of; the head, a* fulcrum` pin; transversing said head coaxially with the gear sector and projecting With both ends into -a pair of co-aligned oblong perforations of the two main walls of the housingbody, said perforations allowingsufiicient play of the fulcrum pin to permit the engaging and disengaging of the gear sector and the toothed rack; and a spring normally acti `g to causeithecomposite element to swing in the pen positions V 2. A parallel wrench composed of a ho sing body having two main walls, a forwardly pro ecting stationary jaw adjacent one edge and a fixed handle extending rearwardly at the opposite edge, amovable jaw opposing said stationary jaw and having a toothed rack slidable transversely within thehousing body, resilient'stop means for restra'ining'the sliding' motion of. said toothedrackr a stationary roller, a` composite element: forming: a lever and a head within a gear sectorratone':

end and' opposing the teeth on the rack, said head" also having 'a cam' profile, the' latter being;

operable upon` the roller; said` roller beingpositioned within the` housing between the fixed handle and the cam 'profile of the head, afulv crum pin' transversingr said head coaxially` withthe gear sector and projectingwith both ends:

into. a pair of co-aligned oblong perforations of the two main Wallsaof' the housing body, said perf'orations allowing sufiicient play of; the fulcrum pin to' permit the engaging and disengag ing' of the gear sector: andthe toothed rack; and` a spring normally acting to cause the compositei a body 'having two main walls, aforwardly: projecting stationary jaw adja'cent one edge and afixed handle extending rearwardly at the=opposite edge, a movablejaw opposing saidstation ary jaw-andhav-ing a toothedrack slidable transversely within the housing body, resilient sto-p, means for restraining the sliding motionof said toothed rack, a stationary roller, a composite element forming a lever and a head with. a gear sector at one end and opposng the teeth .onthe rack, said head also having a .cam profile, the latter beingoperable upon the roller, said roller being positioned within the housing between the fixed handleard the cam profile of the head, a' fulcrum pin transversing said head coaxially with. the gear sector and projecting with both ends into a pair of co-aligned oblong perforations of the two main Walls of the' housing body, said" p'erforations'a'llowing suflicient play of the ful crum pinto permit the engaging and disengaging of thegear'sectorandthe toothed rack.

' ALDO' LAZZARINI:

REFEEENGES' mlm Theffollowing refernces are oi" record in: the, file of` th s patentz. 1

UNITED-STATES PAT-ENTS v Date" 630,821 France Aug-. 29,' 1927.` 

